Equol-containing food composition and production method thereof

Abstract

To provide an equol-containing food composition and a production method thereof, capable of more effectively preventing microbial contamination, and further a production method of equol-containing food composition, the method efficiently collecting equol produced.SOLUTION: A food composition is provided through a production method, and the like, of liquid food composition, the production method obtaining a pH-adjusted liquid food composition which is an equol-containing liquid food composition by including the steps of: (A) culturing at least one kind of equol material selected from a group consisting of daidzein glucoside, daidzein, and dihydrodaidzein with microorganisms that produce equol by using the equol material as culture resource; and (B) adjusting pH by adding a pH adjusting agent to a culture liquid including the equol obtained by the cultivation step.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a food composition containing equol, which is a pH-adjusted liquid food composition or a dried product thereof. The present invention also relates to a method for producing said food composition. [Background technology]

[0002] Isoflavones, which are found in large quantities in legumes such as soybeans and kudzu, are a type of polyphenol and a flavonoid whose basic structure is isoflavone. Recent research has revealed that isoflavones have female hormone (estrogen) and antioxidant effects, and that ingesting isoflavones has a preventive effect against breast cancer, prostate cancer, osteoporosis, hypercholesterolemia, heart disease, menopausal disorders, and other conditions. For example, in soybeans, isoflavones exist as glycosides covalently bound to sugars, such as daidzin, glycitin, and genistin, and only small amounts of aglycones exist. Some of these glycosides are further malonylated or acetylated. When these glycosides enter the human or animal body, they are converted to daidzein, glycitein, and genistein, respectively, by the action of digestive enzymes or β-glucosidase, an enzyme produced by intestinal bacteria. Furthermore, it is known that daidzein is enzymatically converted by the action of intestinal bacteria to dihydrodaidzein, and then to O-desmethylangolensin (O-DMA) or equol.

[0003] Of these metabolic products, equol is known to have the highest estrogenic activity. However, in humans, there are individual differences in isoflavone metabolism, and as mentioned above, only a few people possess intestinal bacteria capable of fermenting daidzein to produce equol, with the rate of such bacteria being approximately 50% in Japanese and approximately 30% in Westerners. Therefore, there has been a problem in that people who do not possess equol-producing bacteria are unable to produce equol in their bodies even if they ingest legume foods such as soybeans.

[0004] In order to overcome these challenges, attempts have been made to produce equol ex vivo using anaerobic microorganisms such as lactic acid bacteria (Patent Documents 1 to 4), and methods for efficiently producing equol and / or efficiently recovering the produced equol have been sought. Patent Document 5 aims to provide an equol-producing microorganism-containing composition that contains viable equol-producing microorganisms that maintain the ability to produce equol and can stably maintain the ability to produce equol even after storage, and discloses that a pH adjuster may be added to control the pH (Patent Document 5), but does not disclose a specific pH adjuster. Furthermore, the pH adjustment is performed in an anaerobic fermentation process, and the preferred pH is 4.6 or higher. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-204296 A. [Patent Document 2] Special Publication No. 2006-504409. [Patent Document 3] JP 2008-61584 A. [Patent Document 4] JP 2010-104241 A. [Patent Document 5] Patent No. 5769419. Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to provide an equol-containing food composition that can be more effectively prevented from being contaminated by microorganisms, and a method for producing the same. Another object of the present invention is to provide a method for producing an equol-containing food composition that efficiently recovers the produced equol, other than or in addition to the above object. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors have discovered the following invention. <1> The food composition comprises equol and is a liquid food composition having an adjusted pH or a dried product thereof. <2> the above <1> The pH value is preferably 3 to 5, and more preferably 3 to 4.

[0008] <3> the above <2> The composition has a pH adjusted with one acid selected from the group consisting of organic acids and inorganic acids, the organic acid is at least one selected from carbonic acid, hydrogen carbonate, citric acid, succinic acid, fumaric acid, lactic acid, gluconic acid, acetic acid, malic acid, ascorbic acid, and benzoic acid; The inorganic acid is preferably at least one selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid. <4> the above <2> In the above, the composition preferably contains at least one inorganic acid selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid.

[0009] <5> the above <1> The pH value is preferably 7 to 11, and more preferably 10 to 11. <6> the above <5> In the above, the pH of the composition is preferably adjusted with one selected from the group consisting of hydroxides of alkali metals and hydroxides of alkaline earth metals. <7> the above <5> In the composition, the pH may be adjusted with one selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, and magnesium hydroxide.

[0010] <8> (A) culturing at least one equol raw material selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein with a microorganism that assimilates the equol raw material to produce equol; and (B) adding a pH adjuster to the equol-containing culture solution obtained in the culturing step to adjust the pH; The method for producing a liquid food composition, comprising the steps of: obtaining a liquid food composition containing equol and having an adjusted pH;

[0011] <9> (A) culturing at least one equol raw material selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein with a microorganism that assimilates the equol raw material to produce equol; (B) adding a pH adjuster to the culture solution containing equol obtained in the culture step to adjust the pH; and (C) a step of drying the liquid obtained in the pH adjustment step; By having the above structure, a powdered food composition containing equol and having an adjusted pH is obtained.

[0012] <10> the above <8> or <9> The adjusted pH is preferably 3 to 5, more preferably 3 to 4. <11> the above <10> The pH adjuster comprises one selected from the group consisting of organic acids and inorganic acids, the organic acid is at least one selected from carbonic acid, hydrogen carbonate, citric acid, succinic acid, fumaric acid, lactic acid, gluconic acid, acetic acid, malic acid, ascorbic acid, and benzoic acid; The inorganic acid is preferably at least one selected from the group consisting of hydrochloric acid, sulfuric acid, and phosphoric acid. <12> the above <10> In the above, the pH adjuster preferably comprises at least one selected from the group consisting of inorganic acids including hydrochloric acid, sulfuric acid, and phosphoric acid.

[0013] <13> the above <8> or <9> The adjusted pH is preferably 7 to 11, and more preferably 10 to 11. <14> the above <13> In the above, the pH adjuster preferably comprises one selected from the group consisting of hydroxides of alkali metals and hydroxides of alkaline earth metals. <15> the above <13> In the above, the pH adjuster is preferably one selected from the group consisting of sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, and magnesium hydroxide. Effect of the Invention

[0014] The present invention provides an equol-containing food composition that can be better prevented from being contaminated by microorganisms, and a method for producing the same. Furthermore, the present invention can provide a method for producing an equol-containing food composition that efficiently recovers the produced equol, in addition to or in addition to the above effects. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present application provides a method for producing a liquid food composition, a method for producing a powdered food composition, and a liquid food composition and a powdered food composition which is a dried product thereof. Hereinafter, a method for producing a liquid food composition and a method for producing a powdered food composition will be described, followed by a description of the liquid food composition and its dried product, the powdered food composition.

[0016] <Method of producing liquid food composition> The method for producing the liquid food composition of the present invention comprises the steps of: (A) culturing at least one equol raw material selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein with a microorganism that assimilates the equol raw material to produce equol; and (B) adding a pH adjuster to the equol-containing culture solution obtained in the culturing step to adjust the pH; By having the above, a liquid food composition containing equol and having an adjusted pH is obtained.

[0017] <<(A) Process>> Step (A) is a step of culturing at least one equol raw material selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein with a microorganism that assimilates the equol raw material to produce equol. The conditions for the culture step are not particularly limited as long as equol can be produced. For example, conventionally known conditions can be used, but the conditions are not limited to these.

[0018] <<Equol raw material>> The equol raw material used in the method of the present invention may be in any form so long as it can be literally used as a raw material for equol. The equol raw material may be in any form as long as it contains at least one selected from the group consisting of daidzein glycoside, daidzein, and dihydrodaidzein, for example, daidzein glycoside itself, daidzein itself, or dihydrodaidzein itself, or a substance containing them, such as soybeans, processed soybeans, soybean hypocotyls, processed soybean hypocotyls, such as soybean extracts, soybean hypocotyl extracts, and purified soybean hypocotyl extracts, and specifically, commercially available isoflavones.

[0019] <<Microorganisms>> The method of the present invention uses a microorganism that has the ability to assimilate an equol raw material and produce equol. In this specification, the "ability to assimilate an equol raw material and produce equol" may be simply referred to as "equol-producing ability." The microorganism capable of producing equol used in the method of the present invention is not particularly limited as long as it is a microorganism capable of producing equol from the above-mentioned equol raw material. The equol raw material is determined in relation to the "equol production ability" of the microorganism. For example, if a certain microorganism A does not have "equol production ability" for daidzein glycoside but has "equol production ability" for daidzein, the equol raw material of the microorganism A will be "daidzein". In this case, a step of converting daidzein glycoside to daidzein may be included before step (A). For example, if a certain microorganism B does not have "equol production ability" for daidzein glycoside and daidzein but has "equol production ability" for dihydrodaidzein, the equol raw material of the microorganism B will be "dihydrodaidzein". In this case, a step of converting daidzein glycoside to daidzein, and then converting daidzein to dihydrodaidzein may be included before step (A). The microorganism may be an anaerobic microorganism, which can produce equol at a temperature of, for example, about 37° C. (e.g., 30 to 42° C.).

[0020] The equol-producing ability can be confirmed by quantifying daidzein, dihydrodaidzein, equol, etc. in the culture. These quantifications can be performed by those skilled in the art based on the descriptions in, for example, WO2012 / 033150, JP 2012-135217, JP 2012-135218, JP 2012-135219, etc. An example of these quantification methods is shown below.

[0021] For example, ethyl acetate is added to the culture solution, which is vigorously stirred and then centrifuged to remove the ethyl acetate layer. If necessary, the same procedure can be performed several times on the same culture solution, and the ethyl acetate layers can be combined to obtain an equol extract. This extract is concentrated and dried under reduced pressure using an evaporator, and dissolved in methanol. This is then filtered using a membrane such as a polytetrafluoroethylene (PTFE) membrane to remove insoluble matter, which can then be used as a high-performance liquid chromatography measurement sample. Examples of high-performance liquid chromatography conditions include, but are not limited to, the following:

[0022] [High performance liquid chromatography conditions] Column: Phenomenox Luna 5uC18, 2.0mm x 150mm (Shimadzu GLC) Mobile phase: Water / methanol [55:45, v / v] Flow rate: 0.2mL / min Column temperature: 40℃ Detection: UV280nm Retention times: dihydrodaidzein 13.8 min, daidzein 19.6 min, glycitein 22.5 min, equol 25.6 min, genistein 35.0 min

[0023] Microorganisms capable of producing equol include, but are not limited to, those classified into the following genera: Genus Adlercreutzia Bacteroides genus Bifidobacterium Clostridium Genus Eggerthella Enterococcus Genus Enterorhabdus Eubacterium genus Genus Finegoldia Lactobacillus Lactococcus Genus Paraeggerthella Pediococcus genus Genus Proteus Genus Sharpea Genus Slackia Streptococcus Genus Veillonella

[0024] Specific examples of microorganisms capable of producing equol include, but are not limited to, the following microorganisms. Adlercreutzia equolifaciens subsp. celatus Adlercreutzia equolifaciens subsp. equolifaciens Bacteroides ovatus Bifidobacterium breve Bifidobacterium longum Clostridium sp. Eggerthella sp. Enterococcus faecalis Enterococcus faecium Enterorhabdus mucosicola Eubacterium sp. Finegoldia magna Lactobacillus fermentum Lactobacillus mucosae Lactobacillus paracasei Lactobacillus plantarum Lactobacillus rhamnosus Lactobacillus sp. Lactococcus garvieae Lactococcus sp. Paraeggerthella sp. Pediococcus pentosaceus Proteus mirabilis Sharpea azabuensis Slackia equolifaciens Slackia isoflavoniconvertens Slackia sp. Streptococcus constellatus Streptococcus intermedius Veillonella sp.

[0025] Among the above-mentioned microorganisms, for example, microorganisms classified into the family Eggerthellaceae, microorganisms classified into the family Bifidobacteriaceae, microorganisms classified into the family Clostridiaceae, microorganisms classified into the family Coriobacteriaceae, microorganisms classified into the family Enterococcaceae, microorganisms classified into the family Eubacteriaceae, microorganisms classified into the family Morganellaceae, microorganisms classified into the family Peptoniphilaceae, microorganisms classified into the family Lactobacillaceae, microorganisms classified into the family Streptococcus, microorganisms classified into the family Veillonellaceae, and microorganisms related thereto can be mentioned. Preferably, the microorganism is classified into the genera Adlercreutzia, Bacteroides, Bifidobacterium, Clostridium, Coriobacterium, Egasella, Enterococcus, Eubacterium, Finegordia, Lactobacillus, Lactococcus, Paraegasella, Pediococcus, Proteus, Chapaea, Slaakia, Streptococcus, Veillonea, or related microorganisms thereof.More preferably, Adrechlautia aequorifaciens subsp. ceratus, Adrechlautia aequorifaciens subsp. aequorifaciens, Bacteroides obatus, Bifidobacterium breve, Bifidobacterium longum, Clostridium sp., Egassella sp., Enterococcus faecalis, Enterococcus faecium, Enterohabdus mucosicola, Eubacterium sp., Finegordia magna, Lactobacillus fermentum, Lactobacillus intestina Lactobacillus subtilis, Lactobacillus mucosae, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus sp., Lactococcus garvieae, Lactococcus sp., Paraegasella sp., Pediococcus pentosaceus, Proteus mirabilis, Sharpea azabuensis, Slachia aequorifaciens, Slachia isoflavonic convertens, Slachia sp., Streptococcus constellatus, Streptococcus intermedius, Veillonea sp.

[0026] Among the above-mentioned microorganisms, any of the microorganisms described below or related microorganisms having similar species properties to these microorganisms can be given as more preferred anaerobic microorganisms. Adlercreutzia equolifaciens subsp. celatus DSM 18785 strain Adlercreutzia equolifaciens subsp. equolifaciens DSM 19450 strain Bacteroides ovatus strain E-23-15 Bifidibacterium breve ATCC 15700 strain Bifidobacterium longum BB536 strain Clostridium sp. HGH136 strain Eggerthella sp. Julong 732 strain Eggerthella sp. YY7918 strain Eggerthella sp. D1 strain Enterococcus faecalis INIA P333 strain Enterococcus faecium strain EPI1 Enterohabdus mucosicola Mt1B8 strain Eubacterium sp. strain D2 Finegoldia magna EPI3 strain Lactobacillus fermentum DPPMA114 strain Lactobacillus intestinalis KTCT13676BP strain Lactobacillus mucosae EPI2 strain Lactobacillus paracasei JS1 strain Lactobacillus plantarum DPPMA24W strain Lactobacillus plantarum DPPMASL33 strain Lactobacillus rhamnosus strain DPPMAAZ1 Lactobacillus rhamnosus INIA P540 strain Lactobacillus sp. Niu-O16 strain Lactococcus garvieae strain 20-92 Paraeggerthella sp. strain SNR40-432 Pediococcus pentosaceus strain CS1 Proteus mirabilis LH-52 strain Sharpea azabuensis ST18 strain Slackia equolifaciens strain DSM 24851 Slackia isoflavoniconvertens DSM 2200 6 stocks Slackia sp. FJK1 strain Slackia sp. NATTS strain Slackia sp. YIT11861 strain Slackia sp. TM-30 strain Streptococcus constellatus strain E-23-17 Streptococcus intermedius A6G-225 strain Veillonella sp. EP strain.

[0027] The above anaerobic microorganisms can be obtained from the depository institutions indicated by their accession numbers. Each accession number indicates that the anaerobic microorganism has been deposited at the following depository institutions: FERM International Patent Organism Depositary (IPOD) http: / / unit.aist.go.jp / pod / ci / index.html DSM German Collection of Microorganisms and Cell Cultures (DSMZ) http: / / www.dsmz.de / KCCM Korean Culture Center of Microorganisms

[0028] In the present invention, anaerobic microorganisms capable of producing equol are cultured under conditions suitable for equol production. In the present invention, the conditions suitable for equol production refer to conditions under which the survival and activity of anaerobic microorganisms capable of producing equol are maintained. More specifically, gas phase conditions (anaerobic conditions) in which anaerobic microorganisms can survive are maintained, and nutrients are provided to support the activity and growth of the anaerobic microorganisms. Various medium compositions suitable for the survival of anaerobic microorganisms are known. Therefore, for the anaerobic microorganisms capable of producing equol shown above, those skilled in the art can select an appropriate medium composition. For example, BHI medium manufactured by Difco and the medium used in the examples can be used, but are not limited to these.

[0029] Water-soluble organic substances can be added to the medium used in the present invention as a carbon source. Examples of water-soluble organic substances include, but are not limited to, the following compounds: sugars such as sorbose, fructose, and glucose; Alcohols such as methanol; Organic acids such as valeric acid, butyric acid, propionic acid, acetic acid, formic acid, etc., or their salts.

[0030] The concentration of the organic matter added to the medium as a carbon source can be appropriately adjusted in order to efficiently grow anaerobic microorganisms in the medium.

[0031] A nitrogen source can be added to the medium. In the present invention, various nitrogen compounds that can be used in normal fermentation can be used as the nitrogen source. Preferred inorganic nitrogen sources are ammonium salts and nitrates. More preferred inorganic nitrogen sources are ammonium sulfate, ammonium chloride, ammonium phosphate, ammonium hydrogen phosphate, potassium nitrate, and sodium nitrate. On the other hand, preferred organic nitrogen sources are amino acids, yeast extract, peptones, meat extract, liver extract, digested serum powder, and the like. More preferred organic nitrogen sources are arginine, cysteine, cystine, citrulline, lysine, yeast extract, and peptones.

[0032] Furthermore, in addition to the carbon and nitrogen sources, other organic or inorganic substances suitable for the production of equol can be added to the medium. For example, the growth and activity of anaerobic microorganisms can be enhanced by adding cofactors such as vitamins and inorganic compounds such as various salts to the medium. For example, the following inorganic compounds, vitamins, and microbial growth cofactors derived from animals and plants can be mentioned.

[0033] Inorganic compounds Vitamins Potassium dihydrogen phosphate Biotin Magnesium Sulfate Folic Acid Manganese Sulfate Pyridoxine Sodium Chloride Thiamine Cobalt chloride Riboflavin Calcium chloride Nicotinic acid Zinc Sulfate Pantothenic Acid Copper Sulfate Vitamin B12 Alum Thioctic acid Sodium molybdate p-aminobenzoic acid Potassium chloride Boric acid etc. Nickel chloride Sodium Tungstate Sodium Selenite Ferrous Ammonium Sulfate

[0034] A conventionally known method can be used to produce a culture solution by adding these inorganic compounds, vitamins, or growth cofactors. The medium can be liquid, semi-solid, or solid. In the present invention, the preferred form of the medium is a liquid medium.

[0035] The medium used in the present invention may contain dextrins. By culturing anaerobic microorganisms in a medium containing dextrins, a liquid containing equol and dextrins can be prepared without contacting the culture with dextrins after the culture. Dextrins can be added to the medium before or during the culture of the microorganism.

[0036] The medium used in the present invention may contain an antifoaming agent, preferably soybean oil, more preferably soybean oil with vitamin E.

[0037] In the method of the present application, the microorganism, particularly the anaerobic microorganism, can be cultured according to a known method for culturing a microorganism. For industrial production, a continuous fermentation system capable of continuously supplying the medium and substrate gas and having a mechanism for recovering the culture can be used.

[0038] In the method of the present invention, when anaerobic microorganisms are used, it is advisable to prevent oxygen from entering the fermentation tank. A commonly used fermentation tank can be used as is. An anaerobic atmosphere can be created by replacing oxygen that enters the fermentation tank with an inert gas such as nitrogen.

[0039] In the step (A) of the present invention, the gas phase is preferably composed of one or more gases including hydrogen. The gas constituting the gas phase is not particularly limited as long as it is composed of one or more gases including hydrogen, but it is preferable that the gas phase contains hydrogen and one or more gases other than hydrogen. Examples of gases other than hydrogen include, but are not particularly limited to, carbon dioxide, nitrogen, carbon monoxide, etc. The hydrogen concentration of the gas is not particularly limited, but examples thereof include 30% or less, 10% or less, and 4% or less. Incidentally, step (A) in the present invention can also be carried out in a closed system such as a bottle or test tube sealed with a rubber stopper without ventilation.

[0040] In order to efficiently recover equol, the amount of mixed gas constituting the gas phase passed through the culture tank can be 0.001 to 2.0 V / V / M gas volume / liquid volume / minute, for example, 0.01 to 2.0 V / V / M gas volume / liquid volume / minute, but is not limited to this amount.

[0041] Depending on the shape of the culture tank, an agitator or the like can be used to thoroughly agitate the medium. By agitating the culture in the culture tank, the opportunities for the medium components and substrate gas to come into contact with the anaerobic microorganisms can be increased, optimizing the efficiency of equol production. The substrate gas can also be supplied as nanobubbles.

[0042] In the present invention, the microorganism may be cultured under normal pressure, but when pressurized, the pressurization conditions are not particularly limited as long as the microorganism can grow under the conditions. Preferred pressurization conditions include, but are not limited to, a pressure in the range of 0.2 MPa or less, for example, a pressure in the range of 0.02 to 0.2 MPa.

[0043] To increase the amount of equol produced, the temperature of the culture tank is not particularly limited, but is preferably 30°C to 40°C, and more preferably 33°C to 38°C. The culture time can be appropriately set depending on the amount of equol produced, the amount of isoflavones remaining, etc. Examples of the culture time include, but are not limited to, 8 to 120 hours, preferably 12 to 72 hours, and particularly preferably 16 to 60 hours.

[0044] <<(B) Process>> Step (B) is a step of adjusting the pH by adding a pH adjuster to the equol-containing culture solution obtained in step (A), i.e., the culturing step. In step (B), the pH of the culture medium is preferably adjusted to the acidic side, specifically to a pH of 3 to 5, and preferably to 3 to 4. By adjusting the pH of the culture medium to the acidic side in this manner, specifically to a pH of 3 to 5, and particularly to 3 to 4, it becomes easier to separate the microorganisms used in step (A), and therefore the efficiency of equol recovery can be increased.

[0045] Furthermore, in step (B), the pH of the culture medium is preferably adjusted to the alkaline side, specifically to a pH of 7 to 11, and preferably to 10 to 11. By adjusting the pH of the culture medium to the alkaline side in this manner, specifically to a pH of 7 to 11, and particularly to 10 to 11, the microorganisms used in step (A) can be lysed, and the efficiency of equol recovery can be increased.

[0046] In the step (B), when the pH is adjusted to the acidic side, the pH adjuster preferably contains at least one acid selected from the group consisting of organic acids and inorganic acids. Organic acids can include, but are not limited to, carbonic acid, bicarbonate, citric acid, succinic acid, fumaric acid, lactic acid, gluconic acid, acetic acid, malic acid, ascorbic acid, and benzoic acid. Additionally, inorganic acids can include, but are not limited to, hydrochloric acid, sulfuric acid, and phosphoric acid.

[0047] In the step (B), when the pH is adjusted to the alkaline side, the pH adjuster preferably contains one selected from the group consisting of hydroxides of alkali metals and hydroxides of alkaline earth metals. Specifically, examples of pH adjusters that adjust the pH to the alkaline side include, but are not limited to, sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, and magnesium hydroxide.

[0048] Although a liquid food composition can be obtained by the above steps (A) and (B), the method of the present invention for obtaining a liquid food composition may include steps other than the above steps (A) and (B), such as, but not limited to, a centrifugation step or a membrane filtration step for removing microorganisms capable of producing equol.

[0049] <Method of producing powdered food composition> The present application further provides a method for producing a powdered food composition. The method further comprises the steps (A) and (B) (C) a step of drying the liquid obtained in the (B) pH adjustment step; By having this, it is possible to obtain a powdered food composition that contains equol and has an adjusted pH.

[0050] <<(C) Process>> The step (C) is a step of drying the liquid obtained in the pH adjustment step (B). (C) The drying step can be carried out by a conventionally known method, for example, heat drying, spray drying, freeze drying, fluidized bed drying, fluidized bed drying, etc., but is not limited to these. The heat drying process can be carried out using, for example, a rotary drum dryer, the spray drying process can be carried out using, for example, a spray dryer, and the freeze drying process can be carried out using, for example, a freeze dryer. The drying method can be carried out using any dryer that can dry a liquid. The product obtained by the drying treatment may be subjected to a pulverization treatment, if necessary.

[0051] The method of the present invention may include steps other than the above steps (A), (B) and (C). For example, after step (B) and before step (C), a step of heat-treating the pH-adjusted liquid obtained in step (B) may be included, and after the heat-treatment step, a centrifugation step and / or a filtration step of removing unnecessary solids from the obtained liquid may be included. Note that, when the pH is adjusted to an alkaline side, particularly to 10 to 11, in step (B), the centrifugation step may not be included, which is preferable in terms of reducing the number of steps. When the process includes a centrifugation step and / or a filtration step for removing unnecessary solids, a clear liquid is obtained, which becomes a liquid food composition suitable for use as a beverage or the like.

[0052] <Food composition> The present application provides a food composition containing equol, which is a pH-adjusted liquid food composition or a dried product thereof. The food composition of the present invention can be obtained by the above-mentioned method, but is not limited thereto.

[0053] <<Liquid food composition>> When the liquid food composition is on the acidic side, its pH should be 3-5, preferably 3-4. Furthermore, when the liquid food composition is on the alkaline side, its pH should be 7-11, and preferably 10-11.

[0054] <<Drying liquid food composition>> The present application also provides a dry product of a liquid food composition comprising equol, the liquid food composition having an adjusted pH. For dry matter, pH is defined as follows: That is, when 50 g of the dried product is dissolved or suspended in 1 L of water, the pH should be within the above-mentioned range, i.e., if on the acid side, the pH should be 3 to 5, preferably 3 to 4, or if on the alkaline side, the pH should be 7 to 11, preferably 10 to 11. A glass diaphragm electrode is preferably used for measuring pH, but a simple device such as pH test paper can also be used.

[0055] When the food composition of the present invention is adjusted to be on the acidic side, the pH is preferably adjusted with one acid selected from the group consisting of organic acids and inorganic acids. In this case, the food composition of the present invention contains one acid selected from the group consisting of organic acids and inorganic acids. Examples of organic acids include, but are not limited to, carbonic acid, hydrogen carbonate, citric acid, succinic acid, fumaric acid, lactic acid, gluconic acid, acetic acid, malic acid, ascorbic acid, and benzoic acid. Additionally, inorganic acids can include, but are not limited to, hydrochloric acid, sulfuric acid, and phosphoric acid.

[0056] When the food composition of the present invention is adjusted to the alkaline side, the pH is preferably adjusted with one selected from the group consisting of hydroxides of alkali metals and hydroxides of alkaline earth metals. In this case, the food composition of the present invention contains one selected from the group consisting of hydroxides of alkali metals and hydroxides of alkaline earth metals. Examples of the hydroxide selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides include, but are not limited to, sodium hydroxide, potassium hydroxide, calcium hydroxide, calcium oxide, and magnesium hydroxide. The present invention will be described below based on examples, but the scope of the present invention is not limited to the following examples. EXAMPLES

[0057] Example 1 (Preparation of pre-culture medium) Anaerobe Basal Broth (manufactured by Thermo Scientific: catalog number CM0957B) was dissolved in a predetermined amount of distilled water (ABB medium), and 1 L was dispensed into a 2 L pressure fermentation tank. After that, the tank was purged with nitrogen gas and sterilized at 121° C. for 15 minutes. (Preparation of main culture medium) Enzyme-treated soybean germ extract (containing aglyconized isoflavones: daidzein, glycitein, and genistein) was added to the ABB medium containing β-cyclodextrin to a final concentration of 6 g / L, and 1 L of the extract was dispensed into a 2 L fermentation tank. The tank was then sterilized at 121°C for 15 minutes after replacing the gas with nitrogen gas.

[0058] (preculture) Adlercreutzia equolifaciens DSM 19450 strain was inoculated into the preculture medium, and then cultured at 37°C for 1 day while continuously supplying anaerobic gas containing hydrogen that had been sterilized using a sterilized filter (pore size: 0.2 μm, material: polyvinylidene fluoride (PVDF)). (main culture) The above pre-cultured strain was inoculated into the main culture medium, and then cultured at 37°C for 2 days while continuously supplying anaerobic gas containing hydrogen that had been sterilized using a sterilized filter (pore size: 0.2 μm, material: PVDF). HPLC analysis confirmed that equol was produced.

[0059] (pH adjustment process) The culture medium in which equol production was confirmed was placed in a glass container, the pH was adjusted, and sterilization by heating was performed. As a comparison, sterilization by heating was performed without adjusting the pH. 1) The pH of the main culture medium was lowered to 3, 4, and 5 by adding citric acid, and sterilization was performed by heating. 2) In addition, the pH of the main culture medium was lowered to 3, 4, and 5 by adding hydrochloric acid, and sterilization was performed by heating. 3) In addition, the pH of the main culture medium was increased to 8, 9, 10, and 11 by adding sodium hydroxide, and sterilization was performed by heating.

[0060] (Confirmation of antibacterial effect) The heat-sterilized liquid obtained in the pH adjustment step was allowed to stand at room temperature for one week, after which equal portions were spread onto standard agar medium, cultured at 37°C for one day, and the number of colonies was counted. The results are shown in Table 1. It was confirmed from Table 1 that, while the number of colonies was too large to count when no adjustment was made, the proliferation of bacteria was suppressed by making the food acidic or alkaline through the pH adjustment step. It was found that microbial contamination can be prevented by providing the pH adjustment step of the present invention, and by using the liquid food composition with an adjusted pH of the present invention or a dried product thereof.

[0061] [Table 1]

[0062] Example 2 In Example 1, the steps up to the pH adjustment step were carried out, and then the following steps were carried out. (Centrifugal sedimentation process) The heat-sterilized culture medium was placed in a 2 mL Eppendorf tube, the insoluble matter was precipitated using a centrifuge, the supernatant was removed, and the amount of precipitate was confirmed. At this time, the centrifugation conditions (rotation speed, time) were changed to see the effect on precipitation. The results are shown in Table 2. Table 2 shows that when the pH was acidified, the amount of precipitate did not change even when the centrifugation speed was reduced, but when the pH was 7 or higher, the apparent amount of precipitate increased. It was confirmed that pH adjustment affects the separation characteristics in the centrifugation process.

[0063] [Table 2]

[0064] Example 3 In Example 1, the steps up to the pH adjustment step were carried out, and then the following steps were carried out. (Centrifugal sedimentation process) After adjusting the pH, the heat-sterilized culture solution was placed in a 40 mL centrifuge tube, insoluble components were precipitated using a centrifuge, and the supernatant was collected.

[0065] (Filtration process) The supernatant recovered by centrifugation was filtered through a PVDF MF membrane (pore size 0.2 μm) and the filtrate was collected. The equol and isoflavones in the filtrate were analyzed by HPLC. The results are shown in Table 3. From Table 3, it can be seen that by making the solution alkaline in the pH adjustment process, the isoflavone concentration is improved and the recovery rate of isoflavones in the filtrate is increased. Since isoflavones other than equol are also expected to have physiological activity, increasing the isoflavone concentration is expected to produce effects that cannot be achieved with equol alone.

[0066] [Table 3]

[0067] Example 4 In Example 1, after the pH adjustment step, the following drying step was carried out. In Example 3, after the filtration step, the following drying step was carried out. (drying process) The filtrate was subjected to freeze-drying to recover a powder.

[0068] (Confirmation of antibacterial effect) The collected powder was spread on a petri dish and left to stand at room temperature for one week. A portion of the powder was then used to make an agar medium by the pour plate method using standard agar medium, and cultured at 37°C for one day, after which the number of colonies was counted. No colonies were detected in any of the powders, suggesting that the bacteriostatic effect was maintained even after drying. The pH of the liquid obtained by dissolving or suspending 50 g of the recovered powder in 1 L of water or in an equivalent ratio is measured and the results are shown in Table 4. It was confirmed from Table 4 that the pH of the liquid obtained by redissolving the recovered powder (the value of "after drying" in Table 4) was almost the same as the pH used in the pH adjustment step in Example 1 (the value of "before drying" in Table 4).

[0069] [Table 4]

[0070] Example 5 The same procedures as in Example 1 were repeated, except that Assaccharobacter celatus DSM 18785 was used instead of Adlercreutzia equolifaciens DSM 19450 strain. The results are shown in Table 5. From Table 5, it was confirmed that, like Example 1, when the pH was not adjusted, the number of colonies was so large that it was impossible to count, whereas by making the solution acidic or alkaline through the pH adjustment step, the proliferation of bacteria could be suppressed. It was found that by providing the pH adjustment step of the present invention, and by using the liquid food composition with an adjusted pH of the present invention or a dried product thereof, microbial contamination can be prevented.

[0071] [Table 5]

[0072] Example 6 The same procedure as in Example 3 was repeated, except that Assaccharobacter celatus DSM 18785 was used instead of Adlercreutzia equolifaciens DSM 19450 strain. The results are shown in Table 6. From Table 6, it can be seen that by making the solution alkaline in the pH adjustment process, the isoflavone concentration is improved and the recovery rate of isoflavones in the filtrate is increased. Since isoflavones other than equol are also expected to have physiological activity, increasing the isoflavone concentration is expected to produce effects that cannot be achieved with equol alone.

[0073] [Table 6]

[0074] Example 7 (Preparation of pre-culture medium) Anaerobe Basal Broth (manufactured by Thermo Scientific: catalog number CM0957B) was dissolved in a predetermined amount of distilled water (ABB medium), and 1 L was dispensed into a 2 L pressure fermentation tank. After that, the tank was purged with nitrogen gas and sterilized at 121° C. for 15 minutes. (Preparation of main culture medium) Soybean germ was crushed, tap water was added to the mixture to a concentration of 100 g / L, and 1 L was dispensed into a 2 L fermentation tank. Enzymes were then added and the mixture was stirred overnight at 50°C to convert the contained isoflavone glycosides into aglycones. Arginine was then added to the mixture to a concentration of 1 g / L, and the mixture was purged with nitrogen gas and sterilized at 121°C for 15 minutes.

[0075] (preculture) Adlercreutzia equolifaciens DSM 19450 strain was inoculated into the preculture medium, and then cultured at 37°C for 1 day while continuously supplying anaerobic gas containing hydrogen that had been sterilized using a sterilized filter (pore size: 0.2 μm, material: polyvinylidene fluoride (PVDF)). (main culture) The above pre-cultured strain was inoculated into the main culture medium, and then cultured at 37°C for 2 days while continuously supplying anaerobic gas containing hydrogen that had been sterilized using a sterilized filter (pore size: 0.2 μm, material: PVDF). HPLC analysis confirmed that equol was produced.

[0076] (pH adjustment process) The culture medium in which equol production was confirmed was placed in a glass container, the pH was adjusted, and sterilization by heating was performed. As a comparison, sterilization by heating was performed without adjusting the pH. The pH of the main culture solution was increased to 8, 9, 10, or 11 by adding sodium hydroxide, and sterilized by heating. Insoluble components were precipitated using a centrifuge in the same manner as in Example 3, and the supernatant was recovered. The precipitate was directly subjected to isoflavone analysis. The results are shown in Table 7.

[0077] As can be seen from Table 7, when soybean germ is used as the raw material, equol and isoflavones are also present in the precipitate; however, by making it alkaline in the pH adjustment process, the concentrations of isoflavone and equol in the precipitate decrease, while the concentrations of isoflavone and equol in the supernatant increase, thereby increasing the recovery rate of isoflavones. The recovery rate of equol can be increased, and isoflavones other than equol are also expected to have physiological activity, so by increasing the isoflavone concentration, it is possible to expect effects that cannot be achieved with equol alone. By removing the water-insoluble soybean germ by centrifugation, a clear aqueous solution can be recovered, making it more suitable for use in beverages and other applications.

[0078] [Table 7]

[0079] Example 8 The same procedures as in Example 7 were repeated, except that Assaccharobacter celatus DSM 18785 was used instead of Adlercreutzia equolifaciens DSM 19450 strain. The results are shown in Table 8. As in Example 7, when soybean germ was used as the raw material, equol and isoflavones were also present in the precipitate; however, by making the precipitate alkaline in the pH adjustment process, the concentrations of isoflavone and equol in the precipitate decreased, while the concentrations of isoflavone and equol in the supernatant increased, thereby increasing the recovery rate of isoflavones. The recovery rate of equol can be increased, and isoflavones other than equol are also expected to have physiological activity, so by increasing the isoflavone concentration, it is possible to expect effects that cannot be achieved with equol alone. By removing the water-insoluble soybean germ by centrifugation, a clear aqueous solution can be recovered, making it more suitable for use in beverages and other applications.

[0080] [Table 8]

Claims

[Claim 1] The food composition is a liquid food composition containing equol, wherein the pH has been adjusted, or the food composition is a dried product thereof.